Effect of electroacupuncture of different acupoint groups on learning-memory ability and expression of IL-1β and TNF-α in hippocampus and prefrontal cortex in rats with Alzheimer's disease

Abstract

To compare the effect of electroacupuncture (EA) of acupoint group for "reinforcing the kidney and regulating Governor Vessel" and acopoint group for "reinforcing the kidney and lung and regulating Governor Vessel" on lear-ning-memory ability and expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) proteins in the hippocampus and prefrontal cortex (PFC) in Alzheimer's disease （AD） rats, so as to explore the efficacy of the two acupoint groups and mechanisms underlying improvement of AD. Forty male SD rats were randomly divided into control, sham operation, model, "Baihui" + "Shenshu" (GV20+BL23, for "reinforcing the kidney and regulating Governor Vessel") EA and GV20+BL23+ "Feishu" (BL13, GV20+BL23+BL13, for "reinforcing the kidney and lung and regulating Governor Vessel") EA groups (n=8 rats in each group). The AD model was established by bilateral injection of amyloid β peptide （Aβ25-35，10 μL) into bilateral hippocampus, and rats of the sham operation group received injection of normal saline. After successful establishment of the model，EA (2 Hz, 2 mA) was applied to these acupoints for 15 min, once daily for 10 days. Then, the learning-memory ability was assessed by using Morris water maze tests, and the expression levels of TNF-α and IL-1β proteins in the PFC and hippocampus tissues were detected by using Western blot. Following modeling, the average escape latency of place navigation test were significantly increased (P<0.05) and the platform crossing times of spatial probe test was significantly decreased in the model group than in the control and sham operation groups (P<0.05). The expression levels of IL-1β and TNF-α proteins in the PFC and hippocampus were apparently up-regulated in the model group than in the control and the sham operation groups (P<0.000 1, P<0.001, P<0.01). After the intervention, the increase of the average escape latency and expression of IL-1β and TNF-α in the PFC and hippocampus, and the decrease of space exploration test were revised in both GV20+BL23 EA and GV20+BL23+BL13 EA groups (P<0.05,P<0.01). No significant differences were found between the GV20+BL23 and GV20+BL23+BL13 EA groups in the above mentioned indexes (P>0.05). EA of both GV20+BL23 and GV20+BL23+BL13 acupoint can improve learning-memory ability of AD rats, which is associated with their effects in down-regulating the expression of IL-1β and TNF-α in the PFC and hippocampus to reduce inflammatory reaction. There were no significant differences between the two acupoint groups in the therapeutic effects.